forkIO can trivially defeat bracket
Consider this program,
import Control.Concurrent
import Control.Exception
main = do
putStrLn "forking"
forkIO $ bracket (putStrLn "forked") (const $ putStrLn "finalize") (const $ putStrLn "hello" >> threadDelay 100000000)
threadDelay 10000
putStrLn "done"
Would you predict that it would print finalize
?
Answer: no. It will print,
forking
forked
hello
done
It would pointed out by an author of a cryptographic library (raaz
) that this is quite bad as it means that secure memory could leak out uncleared.
It's not entirely clear how best to deal with this. Perhaps raise a ThreadKilled
async exception to all running threads during RTS shutdown, followed by a synchronization?
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |